Siloxane-based coatings containing polymers with urea linkages and terminal alkoxysilanes

ABSTRACT

Polyureas made from amino-functional alkoxysilanes, polyisocyanates, and polyfunctional amino- and/or hydroxyl compounds. The polyureas may be moisture-cured in a 1K system or be included in a 2K system with amino and epoxy or acrylate compounds.

This application is a continuation-in-part application of U.S. Pat. No.9,587,143, issued on Mar. 7, 2017, which claims the benefit of U.S.Provisional Application No. 62/067,052, filed on Oct. 22, 2014. Theseapplications and all other publications and patent documents referred tothroughout this nonprovisional application are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure is generally related to siloxane-based coatings.

DESCRIPTION OF RELATED ART

Polyurethane topcoats are the current technology used to provideprotective camouflage, exterior color stability to UV/sunlight, chemicalagent resistance, hydrocarbon and chemical resistance, flexibility,first line corrosion resistance, and a host of other properties for avariety of military assets. The majority of polyurethane topcoatsutilized by the military are qualified to either MIL-DTL-53039E(Coating, Aliphatic Polyurethane, Single Component, Chemical AgentResistant), MIL-DTL-64159B (Camouflage Coating, Water DispersibleAliphatic Polyurethane, Chemical Agent Resistant), or MIL-PRF-85285E(Coating, Polyurethane, Aircraft and Support Equipment). Unfortunately,these polyurethane coatings contain toxic isocyanate-based materialsthat can cause serious health issues for both coating applicators andthe environment, and the development of coating technologies that areboth non-toxic and provide equivalent or greater performance (i.e.,functional properties and exterior durability) than polyurethanecoatings are highly desired by all branches of the military.

An isocyanate is a highly reactive functional group that reacts with ahydroxyl-functional molecule to form a carbamate linkage (aka“urethane”). When several urethane linkages are formed, such as in thecase of a coating, the resulting material is referred to as apolyurethane. Isocyanates can easily react to form polyurethanes atambient temperatures, although the use of a catalyst or heat can beutilized to increase the rate of reaction. Isocyanates can formpolyurethanes using either a two-component (2K) system, which requiresmixing of the isocyanate- and hydroxyl-functional component prior toapplication, or a single-component (1K) system, where theisocyanate-based polymers react with moisture to form carbamic acids,which then decarboxylate to primary amines and subsequently react withremaining isocyanates in the coating to form a self-crosslinked network.

Polyurethane coatings are based on aromatic or aliphatic isocyanates.Aromatic polyurethanes contain aromatic isocyanates, which includemethylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), anddiphenyl carbodiamide-diisocyanate (CD). Aromatic polyurethanes possessexcellent hardness and chemical resistance, although they exhibitgenerally poor flexibility and weathering performance. As a result,aromatic polyurethanes are typically employed as primers and forchemically resistant interior linings where they are not exposed to UVradiation from sunlight. Aliphatic (and cycloaliphatic) polyurethanesare based on variations of either hydrogenated aromatic diisocyanates orlinear diisocyanates, such as isophorone diisocyanate (IPDI), methylenedicyclohexyl diisocyanate (HMDI), and hexamethylene 1,6-diisocyanate(HDI). Aliphatic isocyanate-based polyurethanes possess good weatheringperformance (i.e., color and gloss stability) and flexibility, whichrender them an excellent choice for military and aerospace topcoats,automotive refinish clearcoats, and high-performance architecturalcoatings. Although the aforementioned materials are examples ofdiisocyanate (two reactive groups per molecule) molecules, it is notuncommon for coatings to contain polymeric isocyanates, such ashexamethylene diisocyanate homopolymers. However, these higher molecularweight and less volatile adducts are still considered toxic.

Most isocyanates are highly reactive molecules with a high vaporpressure, and airborne exposure to individuals can often result insevere irritation to the eyes, nose, throat, and skin. The spraying(aerosolized particles), brushing, or rolling of materials that containisocyanates can induce symptoms of asthma, such as coughing, shortnessof breath, wheezing, swelling of the arms and legs, and tightness ofchest, in addition to hypersensitivity pneumonitis, which is a lungdisease whose symptoms include fever, body aches, and cough with phlegmor sputum. The Department of Health Services of California estimatesthat about one in twenty people who work with isocyanates become“sensitized”, meaning that an individual can experience a variety ofadverse health conditions from subsequent exposures, even if theexposure is at extremely low levels. To reduce exposure, specialpersonal protective equipment (PPE), such as Tyvek® suites, nitrilegloves, and forced air respirators must be worn by individuals whenapplying isocyanate-containing materials, such as the currentpolyurethane topcoats used by the military.

Advances in organosilicon chemistry have led to the large scaleproduction of “hybrid” materials that contain both organic (e.g.,carbon, hydrogen) and inorganic (silicon) segments. Coatings thatcontain silicon-oxygen bonds possess an inherent durability advantageover traditional organic-based materials. The Si—O bond, which has abond enthalpy of 110 kcal/mol, is stronger than the carbon-hydrogen (99kcal/mol) and carbon-carbon (83 kcal/mol) bonds found in organiccoatings, such as polyurethanes, thereby leading to an increase inthermal stability and resistance to oxidative degradation byUV/sunlight. Organosilicon-based materials, such as polysiloxanes, arealso relatively non-toxic to humans.

Two-component (2K) polysiloxane coatings, also referred to as“siloxanes”, are commercially available by several manufacturers for usein the protective and marine coatings markets. These coatings are basedon hybrid cure materials that contain both reactive organic groups andmoisture-curable alkoxysilane groups, where one portion of the coatingis crosslinked via the ambient reaction between organic groups, such asamines and epoxies, while the other portion forms a three-dimensionalpolysiloxane network via moisture hydrolysis of the alkoxysilanes andcondensation of the resulting silanols. These coatings offer goodexterior durability, hardness, and chemical resistance. However, thesecoatings suffer from low flexibility due to their high crosslinkdensity, which prohibits them from being used as topcoats for militaryaerospace and vehicle applications.

BRIEF SUMMARY

Disclosed herein is a polyurea made by a method comprising: reacting anamino-functional alkoxysilane with a polyisocyanate to form one or moreadducts having an unreacted isocyanate group; and reacting the adductswith one or more polyfunctional amino- and/or hydroxyl compounds and apolyisocyanate to form the polyurea. At least one of the polyfunctionalamino- and/or hydroxyl compounds comprises an amino group. At least oneof the polyfunctional amino- and/or hydroxyl compounds comprises ahydroxyl group. Isocyanate groups do not react with other isocyanategroups. The polyurea comprises at least two residues of thepolyfunctional amino- and/or hydroxyl compounds. The polyurea containsno unreacted isocyanate groups.

Also disclosed herein is a method comprising: providing a compositioncomprising a polyurea; and moisture-curing the composition. The polyureais made by a method comprising: reacting an amino-functionalalkoxysilane with a polyisocyanate to form one or more adducts having anunreacted isocyanate group; and reacting the adducts with one or morepolyfunctional amino- and/or hydroxyl compounds and a polyisocyanate toform the polyurea. The polyurea comprises at least two residues of thepolyfunctional amino- and/or hydroxyl compounds. Isocyanate groups donot react with other isocyanate groups. The polyurea contains nounreacted isocyanate groups.

Also disclosed herein is a composition comprising: an amine-functionalcompound or an epoxy- or acrylate-functional compound and theimmediately above polyurea. The composition does not comprise both theamine-functional compound and the epoxy- or acrylate-functionalcompound.

Also disclosed herein is a coating composition comprising: anamine-functional compound; the immediately above polyurea; and an epoxy-or acrylate-functional compound. The coating composition is atwo-component system.

Also disclosed herein is a method comprising: providing a compositioncomprising a polyurea and moisture-curing the composition. The polyureais made by a method comprising: reacting an amino-functionalalkoxysilane with a polyisocyanate to form an adduct; and reacting theadduct with a compound having two or more amino and/or hydroxyl groupsto form the polyurea. The polyurea contains no unreacted isocyanategroups.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation will be readily obtained by reference tothe following Description of the Example Embodiments and theaccompanying drawings.

FIG. 1 shows a polyurea having an aspartic ester-containing backbone.

FIG. 2 shows a polyurea having polyester backbone.

FIG. 3 shows a polyurea having a polysiloxane backbone andester-containing N-substituted groups.

FIG. 4 shows the results of bending tests of the prior (left) andpresent (right) coatings.

FIG. 5 shows a polyurea having a cycloaliphatic backbone.

FIG. 6 shows a polyurea having an aliphatic backbone andester-containing N-substituted groups.

FIG. 7 shows a polyurea having an asymmetric structure andester-containing N-substituted groups.

FIG. 8 shows a polyurea based on an aromatic diamine.

FIG. 9 shows a variety of compounds made from a single reaction.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In the following description, for purposes of explanation and notlimitation, specific details are set forth in order to provide athorough understanding of the present disclosure. However, it will beapparent to one skilled in the art that the present subject matter maybe practiced in other embodiments that depart from these specificdetails. In other instances, detailed descriptions of well-known methodsand devices are omitted so as to not obscure the present disclosure withunnecessary detail.

Disclosed are flexible, exterior durable, two-component (2K)siloxane-based coatings using flexible urea polymers with terminalalkoxysilanes. These polymers possess urea linkages (N-substituted andnon-N-substituted), a flexible backbone, and moisture-curablealkoxysilane groups that hydrolyze and condense to form exterior durablepolysiloxane linkages. These polymers are compatible with materials usedin two-component siloxane-based systems, thereby allowing the crosslinkdensity of the two components to be reduced so that flexibility isimproved, yet still maintaining sufficient coating hardness, cure times,solvent resistance and exterior durability (e.g., color and glossretention). Coatings based on these systems have application as gloss,semi-gloss, and flat/matte finish topcoats for military and commercialassets. The coatings are also low in viscosity and volatile organiccompounds (VOCs), and are easily spray-applied via high-volume,low-pressure (HVLP) equipment. These coatings are isocyanate-free andcan provide a safer alternative to the polyurethane topcoats currentlyused by the military, commercial aerospace, and the automotive refinishmarkets.

The two-component (2K) polysiloxane coatings contain flexible polymerswith urea linkages and terminal alkoxysilanes. The urea linkages in thepolymers can be N-substituted or non-N-substituted, althoughN-substituted may be preferred. The urea linkages are located near theterminal alkoxysilanes and the flexible backbone. The flexible backbonemay be aliphatic, cycloaliphatic, aromatic, polyester, polyurethane,polycarbonate, polyether, polysulfide, polysiloxane, or a combinationthereof, and the N-substituted groups can be C1-C12 alkyl, cycloalkyl,aryl, ester-containing aliphatic, ester-containing fluorinatedaliphatic, amide-containing aliphatic, polysiloxane, or any combinationthereof. The flexible alkoxysilane-terminated urea polymer, based ontotal binder solids, can range from 1-50 weight % of the formulation.

In addition to the flexible polymer, the two components (two parts thatreact once mixed) in the coating are based on amine- and epoxy- oramine- and acrylate-functional materials. The amines can be a hybridorganic-inorganic material, such as an amino-functionalpolydimethylsiloxane, 3-aminopropyltriethoxysilane, or3-aminopropylmethyldiethoxysilane, or an organic-based material, such asan amino-functional polyether. The epoxy can be a hybrid material, suchas an epoxy-functional polydimethyldiphenylsiloxane, or an organicmaterial, such as a cycloaliphatic epoxy or aliphatic epoxy.Acrylic-functional materials, such as 1,6-hexanedioldiacrylate, can beused in lieu or in combination with epoxies. These two-componentcoatings can also contain pigments, fillers, additives, solvents, andcatalysts.

The coating may be made by mixing the two components, applying themixture to a surface, and allowing the mixture to cure to a coating. Anyapparatus for mixing and applying the mixture may be used, and suchequipment is known in the art. The mixing and applying may also beperformed simultaneously.

Either or both of the components may optionally include one or more of acatalyst, a reactive diluent, a pigment, a filler, a solvent, or anadditive, though pigments and fillers are not typical in thealkoxysilane-terminated polyurea component and catalysts are nottypically in the epoxy or acrylate component. Such materials are knownin the art of 2K coatings. The mixture may be formulated with, forexample, up to 50 wt %, 1-50 wt %, or 5-50 wt % of thealkoxysilane-terminated polyurea.

The first component (part A) includes an amine-functional compound andan alkoxysilane-terminated polyurea. The amine-functional compound canbe a monoamine, diamine, triamine, primary amine, or secondary amine.Suitable amine-functional compounds include, but are not limited to, anamino-functional polydimethylsiloxane, an amino-functionalpolydimethyldiphenylsiloxane, 3-aminopropyltriethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane,1-aminomethyltrimethoxysilane, an aliphatic monoamine, an aliphaticdiamine, a cycloaliphatic diamine, or an amino-functional polyether.

The polyurea has terminal alkoxysilane groups formed by reacting anamine-functional alkoxysilane with a polyisocyanate to form an adduct,and has no unreacted isocyanate groups. As used herein, “no unreactedisocyanate groups” means that enough isocyanate-reactive groups are usedto react with all isocyanate groups, though it is possible that traceamounts of unreacted isocyanate remain. When there is an excess ofisocyanate groups relative to amine groups, the adduct may be reactedwith a difunctional amino- or hydroxyl compound to consume all unreactedisocyanate groups. A typical reaction scheme is shown below. Note thatthe use of a diol forms urethane groups in the polyurea. Each of thereactants may include more than one such compound of the generalstructure. Other reactants may be present or excluded.

n(R¹O)_(a)R¹ _(3-a)Si—(CH₂)₃—NHR²+R³−(NCO)_(n+1)→[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NCO  (1)

2[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NCO+NHR⁴—R⁵—NHR⁴(diamine)→{[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—NR⁴}₂—R⁵  (2)

2[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NCO+HO—R⁵—OH(diol)→{[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—O}₂—R⁵  (3)

The value a is 1, 2, or 3, in that there is at least one alkoxy groupbound to the silicon atom. The value n is a positive integer, in thatthe polyisocyanate has n+1 isocyanate groups. The polyurea may be amixture of the above compounds with other polyureas. The mixture mayinclude a small amount of polyureas where all the isocyanate groups arereacted with amine-functional alkoxysilanes as shown below.

n+1(R¹O)_(a)R¹ _(3-a)Si—(CH₂)₃—NHR²+R³−(NCO)_(n+1)→[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n+1)—R³  (4)

Larger molecules may also be made, especially when less amine-functionalalkoxysilane is used, as shown below using a diol. However, an amount ofamine-functional alkoxysilane is typically used so that compounds in thefirst set of reactions above predominate. Thus, the first component mayinclude at least one such compound having a molecular weight of lessthan 3000, 2500, or 2000, and at least 50, 75, or 90 wt% of all thepolyureas in the first component may be of such molecular weights.

5(R¹O)₃Si—(CH₂)₃—NHR²+3R³—(NCO)₃→2[(R¹O)₃Si—(CH₂)₃—NR²—CO—NH]₂—R³—NCO+(R¹O)₃—NR²—CO—NH—R³—(NCO)₂+2HO—R⁵—OH→{[(R¹O)₃Si—(CH₂)₃—NR²—CO—NH]₂—R³—NH—CO—O—CO—NH}₂—R³—NH—CO—NR²—(CH₂)₃—Si(OR³)₃  (5)

Each R¹ group of the amine-functional alkoxysilane may be anindependently selected alkyl group, such that all the R¹ groups are thesame or may be of more than one type. Each R² group of theamine-functional alkoxysilane may be an independently selected hydrogen,aryl, alkyl, cycloalkyl, ester-containing aliphatic, ester-containingfluorinated aliphatic, amide-containing aliphatic, or polysiloxane. Theamine-functional alkoxysilane is a different compound from the polyureaitself, and may be free of urea groups. Suitable amine-functionalalkoxysilanes include, but are not limited to,N-butyl-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane,N-methyl-3-aminopropyltrimethoxysilane, orN-[3-(trimethoxysilyl)propyl]-O-alanine butyl ester.

The R³ group of the polyisocyanate may be aliphatic, cycloaliphatic, oraromatic. Aliphatic isocyanates may provide for better flexibility andweatherability in the coating. Suitable polyisocyanates include, but arenot limited to, hexamethylene diisocyanate, a homopolymer ofhexamethylene diisocyanate, toluene diisocyanate, methylene diphenyldiisocyanate, and mixtures thereof. Commercially available polymericisocyanates may include mixtures, such as dimers and trimers ofhexamethylene diisocyanate.

Each R⁴ group of the difunctional amino compound may be an independentlyselected hydrogen, aryl, alkyl, cycloalkyl, ester-containing aliphatic,ester-containing fluorinated aliphatic, amide-containing aliphatic, orpolysiloxane. Each R⁵ group of the difunctional amino- or hydroxylcompound may include an independently selected aliphatic,cycloaliphatic, aromatic, polyester, polyether, polysulfide,polyurethane, polycarbonate, polysiloxane, and any combination thereof.Suitable difunctional amino- or hydroxyl compounds include, but are notlimited to, aspartic acid,N,N′-(2-methyl-1,5-pentanediyl)bis-1,1′,4,4′-tetraethyl ester, anunsaturated polyester, a caprolactone-based polyester, or ahydroxyl-propyl terminated polydimethylsiloxane.

The alkoxysilane-terminated polyurea may also be any of those disclosedin U.S. Pat. No. 9,139,753 or U.S. Patent Appl. Publ. No. 2015/0291837,both of which are incorporated herein by reference, and certain subjectmatter thereof included below. The teachings of these applications mayapply to the presently disclosed polyureas.

In an exemplary embodiment, the aforementioned polymer is formed byreacting 30-95% of the isocyanate groups on the polyisocyanate with anon-substituted or N-substituted amino-functional alkoxysilane, and5-70% of the isocyanate groups on the aliphatic polyisocyanate with adiamine, secondary diamine, or diol, such that no unreacted isocyanateremains in the polymer. Addition of the diamine or diol forms largermolecules, which increases the overall molecular weight of the polymer.

The polyisocyanate can be aliphatic, cycloaliphatic or aromatic.Aliphatic polyisocyanates are more weatherable (i.e., exterior durable)than aromatic polyisocyanates, thereby providing greater color stabilitywhen utilized for exterior coatings. Aliphatic polyisocyanates can havevarious numbers of reactive isocyanate (NCO) groups per molecule,depending on their structure. Typically, the number ranges from 2.5 to5.5. For the present coating composition, the aliphatic polyisocyanatemay have greater than 2 NCO groups per molecule. Suitable aliphaticpolyisocyanates include, but are not limited to, structures based onisocyanurates (e.g., HDI and IPDI trimers), biurets, uretdiones,allophanates, oxadiazinetriones, iminooxadiazinedione, and prepolymerscontaining urethanes. Mixtures of these isocyanates can also be used.There are many commercially available aromatic, aliphatic, andcycloaliphatic polyisocyanates.

The N-substituted amino-functional alkoxysilane can be N-substituted3-aminopropyltrialkoxysilane, N-substituted3-aminopropylalkyldialkoxysilane or N-substituted dialkylalkoxysilane,where the alkyl group attached to the silicon atom can be methyl orethyl, and the alkoxy group attached to the silicon atom can be methoxy,ethoxy, n-propoxy, or n-butoxy.

The N-substituted group of the N-substituted amino-functionalalkoxysilane can be C1-C12 alkyl, cycloalkyl, or aryl. Examples include,but are not limited to, N-methyl-3-aminopropyltrimethoxysilane,N-ethyl-3-aminopropyltriethoxysilane,N-methyl-3-aminopropyltributoxysilane,N-ethyl-3-aminopropyltripropoxysilane,N-iso-propyl-3-aminopropyltrimethoxysilane,N-tent-butyl-3-aminopropyltrimethoxysilane,N-butyl-3-aminopropyltrimethoxysilane,N-butyl-3-aminopropylmethyldimethoxysilane,N-butyl-3-aminopropyldimethylmethoxysilane,N-butyl-3-aminopropyltriethoxysilane,N-butyl-3-aminopropyltripropoxysilane,N-butyl-3-aminopropyltributoxysilane,N-iso-butyl-3-aminopropyltrimethoxysilane,N-cyclohexyl-3-aminopropyltrimethoxysilane,N-hexyl-3-aminopropyltrimethoxysilane,N-nonyl-3-aminopropytrimethoxysilane andN-dodecyl-3-aminopropyltrimethoxysilane, andN-phenyl-3-aminopropyltrimethoxysilane. Many of these are commerciallyavailable.

The N-substituted group of the N-substituted amino-functionalalkoxysilane can also be an ester-containing aliphatic orester-containing fluorinated aliphatic, which are formed by the MichaelAddition (conjugate addition) reaction between a molecule with areactive “ene” group, such as an acrylate, and3-aminopropyltrialkoxysilane, 3-aminopropylalkyldialkoxysilane, or3-aminopropyldialkylalkoxysilane. Conditions for forming MichaelAddition adducts with an amine are well known in the literature.Suitable acrylates include, but are not limited to, methyl acrylate,ethyl acrylate, butyl acrylate, cyclohexyl acrylate, hexyl acrylate,2-ethylhexyl acrylate, octyl acrylate, 4-tert-butylcyclohexyl acrylate,diethyl maleate, dimethyl maleate, dibutyl maleate, ethylene glycolmethyl ether acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate,2,2,2-trifluoroethyl acrylate, and3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl acrylate. Examples include,but are not limited to, methyl3-((3-(trimethoxysilyl)propyl)amino)propanoate, butyl3-((3-(trimethoxysilyl)propyl)amino)propanoate, 2-ethylhexyl3-((3-(trimethoxysilyl)propyl)amino)propanoate, octyl3-((3-(trimethoxysilyl)propyl)amino)propanoate, 3,3,3-trifluoropropyl3-((3-(trimethoxysilyl)propyl)amino)propanoate, dimethyl(3-(trimethoxysilyl)propyl)aspartate, and diethyl(3-(trimethoxysilyl)propyl)aspartate.

The N-substituted group of the N-substituted amino-functionalalkoxysilane can also be an amide-containing aliphatic, which is formedby the Michael Addition (conjugate addition) reaction between a moleculewith a reactive “ene” group, such as an acrylamide, and3-aminopropyltrialkoxysilane, 3-aminopropylalkyldialkoxysilane, or3-aminopropyldialkylalkoxysilane. Suitable acrylamides include, but arenot limited to, N-ethylacrylamide, N-propylacrylamide,N-tert-butylacrylamide, N-cyclohexylacrylamide, N-ethyl maleimide, andN,N′-diethylmaleamide. Examples include, but are not limited to,N-propyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide,N-butyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide,N-cyclohexyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide, and1-ethyl-3-((3-(trimethoxysilyl)propyl)amino)pyrrolidine-2,5-dione.

The secondary diamine is a molecule that contains two reactive secondaryamine groups, or N-substituted groups, with a chain of atoms between.These secondary diamines are used for reacting with the isocyanategroups, extending the chain length between the terminal alkoxysilanes,and increasing the overall molecular weight of the N-substituted ureapolymer. The secondary diamines form N-substituted urea linkages oncereacted with the isocyanate groups. The secondary diamines provideincreased flexibility, exterior durability, and faster tack-free times.A mixture of secondary diamines can be used to provide tailoredflexibility and hardness. The secondary diamine chain extender can be analiphatic, cycloaliphatic, or aromatic chain with secondary diamines,such as a bis(secondary diamine). The secondary diamine chain extendercan also be, but is not limited to, a dimethylpolysiloxane chain withsecondary diamines, a methylphenylpolysiloxane chain with secondarydiamines, a polyether chain with secondary diamines, a polysulfide chainwith secondary diamines, or a mixture thereof.

The N-substituted groups of the N-substituted secondary diamines can beC1-C12 alkyl, cycloalkyl, or ester-containing aliphatic. TheN-substituted groups can be produced by reductive amination. TheN-substituted groups can also be produced by reacting an amine with amolecule containing a reactive “ene” group, such as an acrylate ormaleate, via a Michael Addition (conjugate addition) reaction. SuitableN-substituted secondary diamines include, but are not limited to, thefollowing:

Structure Name

N¹,N³-dimethylpropane-1,3-diamine

N¹,N³-diethylpropane-1,3-diamine

N¹,N⁵-diisopropyl-2-methylpentane-1,5- diamine

N¹,N⁶-dimethylhexane-1,6-diamine

N¹,N⁶-bis(3,3-dimethylbutan-2-yl)hexane-1,6- diamine

1,1′-(1,2-phenylene)bis(N- methylmethanamine)

N,3,3,5-tetramethyl-5- ((methylamino)methyl)cyclohexan-1-amine

N-isopropyl-3-((isopropylamino)methyl)-3,5,5-trimethylcyclohexan-1-amine

tetraethyl 2,2′-((2-methylpentane-1,5- diyl)bis(azanediyl))disuccinate

4,4′-methylenebis(N-isopropylcyclohexan-1- amine)

tetraethyl 2,2′-((methylenebis(cyclohexane-4,1-diyl)bis(azanediyl)disuccinate

4,4′-methylenebis(N-(sec-butyl)cyclohexan-1- amine)

dibutyl 3,3′-(hexane-1,6- diylbis(azanediyl)dipropionate

3,3′-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bis(N-methylpropan-1-amine)

N,N′-isopropylaminopropyl terminated poly- dimethylsiloxane

N,N′-ethylaminoisobutyl terminated polydi- methylsiloxane

Several secondary diamines are commercially available.

A person skilled in the art understands that secondary triamines,secondary tetramines, secondary pentaamines, or larger, could also beutilized to increase molecular weight, although the viscosity of theresulting N-substituted polyurea polymer would be greater than if usinga similar sized secondary diamine.

As discussed, numerous aliphatic, cycloaliphatic or aromaticpolyisocyanates, diamines or diols, and N-substituted ornon-N-substituted amino-functional alkoxysilanes can be utilized toprovide alkoxysilane-terminated polyureas, thus providing the ability togenerate a large variety of polymers that possess differences inmolecular weight, structure, and properties (e.g., cure times, hardness,flexibility, solvent resistance and exterior weathering resistance).

In an example synthesis of an N-substituted urea polymer with terminalalkoxysilanes, the polymer is the reaction product of (i) an aliphatic,cycloaliphatic or aromatic polyisocyanate with at least 2 isocyanate(NCO) reactive groups per molecule, where (ii) 30-95% of the isocyanategroups are reacted with an N-substituted amino-functional alkoxysilane,and (iii) 5-70% of the isocyanate groups are reacted with a diamine,secondary diamine or diol chain extender, such that no unreactedisocyanate remains in said polymer. Preferably, the N-substituted ureapolymer with terminal alkoxysilanes is the reaction product of (i) analiphatic, cycloaliphatic or aromatic polyisocyanate with at least 2isocyanate (NCO) reactive groups per molecule, where (ii) 50-80% of theisocyanate groups are reacted with an N-substituted amino-functionalalkoxysilane, and (iii) 20-50% of the isocyanate groups are reacted witha diamine, secondary diamine or diol chain extender, such that nounreacted isocyanate remains in said polymer. More preferably, theN-substituted urea polymer with terminal alkoxysilanes is the reactionproduct of (i) an aliphatic, cycloaliphatic or aromatic polyisocyanatewith at least 2 isocyanate (NCO) reactive groups per molecule, where(ii) 60-70% of the isocyanate groups are reacted with an N-substitutedamino-functional alkoxysilane, and (iii) 30-40% of the isocyanate groupsare reacted with a diamine, secondary diamine, or diol chain extender,such that no unreacted isocyanate remains in said polymer.

A person skilled in the art understands that a small amount ofisocyanate groups (e.g., 1-5%) could remain unreacted in the polymer,and thereby could be used to assist with adhesion to a substrate, orcould be used to react with an isocyanate-reactive material that is notdiscussed herein. However, reacting a small percentage of the isocyanategroups on a polymer with a non-disclosed material is not expected tochange the properties of the polymer, and should not be considered aseparate polymer. For the purpose of making isocyanate-free coatings, itis recommended that all isocyanate groups be reacted during synthesis ofthe N-substituted urea polymer.

The structure in FIG. 5 is an example of an N-substituted urea polymerwith terminal alkoxysilanes that is synthesized using an aliphaticpolyisocyanate based on an HDI isocyanurate trimer,N-butyl-3-aminopropyltrimethoxysilane (an N-substituted amino-functionalalkoxysilane), andN-isopropyl-3-((isopropylamino)methyl)-3,5,5-trimethylcyclohexan-1-amine(a cycloaliphatic secondary diamine). In this example, all newly formedN-substituted urea groups possess either a butyl or isopropyl group.

The structure in FIG. 6 is an example of an N-substituted urea polymerwith terminal alkoxysilanes that is synthesized using an aliphaticpolyisocyanate based on an HDI isocyanurate trimer, an N-substitutedamino-functional alkoxysilane formed from the Michael Addition reactionof butyl acrylate and 3-aminopropyltrimethoxysilane, andN¹,N³-diethylpropane-1,3-diamine (an aliphatic secondary diamine).

Alternative structures of N-substituted urea polymers with extendedchains and terminal alkoxysilanes can be formed by utilizing a mixtureof two different aliphatic isocyanates, an N-substitutedamino-functional alkoxysilane, and a secondary diamine.

The structure in FIG. 7 is an example of an N-substituted urea polymerwith terminal alkoxysilanes that is synthesized using a 1:1 mixture ofan aliphatic polyisocyanate based on an HDI isocyanurate trimer and analiphatic polyisocyanate based on a uretdione,N-butyl-3-aminopropyltrimethoxysilane (an N-substituted amino-functionalalkoxysilane), and N¹,N⁶-dimethylhexane-1,6-diamine (an aliphaticsecondary diamine). The N-substituted amino-functional alkoxysilane isreacted with ˜60% of the isocyanate groups, whereas the secondarydiamine is reacted with ˜40% of the isocyanate groups. The structure isasymmetric due to the use of two different aliphatic polyisocyanates.

The structure in FIG. 8 is an example of an N-substituted urea polymerwith terminal alkoxysilanes that is synthesized using an aliphaticpolyisocyanate based on a HDI isocyanurate trimer,N-butyl-3-aminopropyltrimethoxysilane (an N-substituted amino-functionalalkoxysilane), and 1,3-phenylenedimethanamine (an aromatic diamine). TheN-substituted amino-functional alkoxysilane is reacted with ˜66% of theisocyanate groups, whereas the diamine is reacted with ˜33% of theisocyanate groups.

A reactive diluent also may be used for modifying the properties of the2K coating, such as increasing the flexibility or hardness, reducingsolvent content and viscosity, increasing cleanability, or increasingweatherability (i.e., resistance to exterior degradation from sunlight).The reactive diluent can be a polysiloxane with at least 2 hydrolyzablealkoxysilane groups, such as, but not limited to,poly(dimethoxysiloxane), poly(diethoxysiloxane), methoxy-functionaldimethylpolysiloxane, methoxy-functional methylphenylpolysiloxane,ethoxy-functional dimethylpolysiloxane, and structures based ontetraethyl orthosilicate. The reactive diluent can also behydroxyl-functional versions of these polysiloxanes or hydroxyl propylterminated polysiloxanes. Many of these are commercially available.

The reactive diluent can also be an alkyl-functional alkoxysilane, wherethe alkyl group is C1-C16 alkyl, cycloalkyl or fluorinated alkyl, andthe alkoxysilane group is trimethoxysilane, triethoxysilane,methyldimethoxysilane, methyldiethoxysilane, dimethylmethoxysilane, anddimethylethoxysilane. Examples include, but are not limited to,propyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane,octyltriethoxysilane, hexadecyltrimethoxysilane,cyclohexyltriethoxysilane, (3,3,3-trifluoropropyl)trimethoxysilane, and1H,1H,2H,2H-perfluorooctyltriethoxysilane.

The reactive diluent can also be a polysiloxane-urea polymer withhydrolysable alkoxysilane groups. These reactive diluents are formed byreacting a polysiloxane with primary diamines, or a polysiloxane withsecondary diamines, and 3-isocyanatopropyltrimethoxysilane or3-isocyanatotriethoxysilane. They can also be formed by reacting adiisocyanate-functional polysiloxane with an N-substituted3-aminopropylalkoxysilane. The polysiloxane can be adimethylpolysiloxane or methylphenylpolysiloxane. The N-substitutedgroups of the secondary diamines (attached to the polysiloxane) andN-substituted 3-aminopropylalkoxysilane can be C1-C12 alkyl, cycloalkyl,aryl, or ester-containing aliphatic. The alkoxysilane group of theN-substituted 3-aminopropylalkoxysilane can be trimethoxysilane,triethoxysilane, methyldimethoxysilane, methyldiethoxysilane,dimethylmethoxysilane, and dimethylethoxysilane. There are severalcommercial sources of the raw materials for synthesizing these reactivediluents. Example structures of these synthesized reactive diluentsinclude, but are not limited to, the following:

Structure Name

bis((3- triethoxysilyl)propyl)urea adduct based on N,N′-ethylaminoisobutyl terminated polydimethylsiloxane

bis((3- triethoxysilyl)propyl)urea adduct based on aminopropylterminated polydimethylsiloxane

bis(N-substituted 3-aminopropylalkoxysilane) urea adduct based ondiisocyanate-functional polydimethylsiloxane

Reactive diluents that contain N-substituted urea groups are used due totheir reduced hydrogen bonding character, lower viscosity and reducedsolvent requirements.

The reactive diluent can also be an aliphatic or cycloaliphaticN-substituted urea with hydrolysable alkoxysilane groups. These reactivediluents are formed by reacting an aliphatic or cycloaliphatic secondarydiamine with 3-isocyanatopropyltrimethoxysilane or3-isocyanatotriethoxysilane. The 3-isocyanatopropyltrimethoxysilane and3-isocyanatotriethoxysilane are both commercially available. Suitablesecondary diamines are the same as those utilized for synthesizing theN-substituted urea polymer with terminal alkoxysilanes. Examplestructures of these synthesized reactive diluents include, but are notlimited to, the following:

Structure Name

1,1′-(hexane-1,6-diyl)bis(1-(3,3- dimethylbutan-2-yl)-3-(3-(triethoxysilyl)propyl)urea)

1-isopropyl-1-((5-(1-isopropyl-3- (3-(triethoxysilyl)propyl)ureido)-1,3,3-trimethylcyclohexyl)methyl)- 3-(3-(triethoxysilyl)propyl)urea

1,1′-(hexane-1,6-diyl)bis(1-methyl- 3-(3-(triethoxysilyl)propyl)urea)

tetraethyl 2,2′-(4,4,22,22- tetraethoxy-12-methyl-9,17-dioxo-3,23-dioxa-8,10,16,18-tetraaza- 4,22-disilapentacosane-10,16-diyl)disuccinate

The reactive diluent can also be a polyester-urethane polymer withhydrolyzable alkoxysilane groups. These reactive diluents are formed byreacting an aliphatic or cycloaliphatic polyester polyol with3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane,or (isocyanatomethyl)trimethoxysilane. The polyester polyol should belinear or slightly branched, and can be utilized to provide increasedflexibility. Suitable polyester polyols include unsaturated polyesters,such as 1,3-benzenedicarboxylic acid, polymer with2,2-dimethyl-1,3-propanediol, 1,2-ethanediol, hexanedioic acid, and1,6-hexanediol, and saturated polyesters such as those based oncaprolactone. Many polyester polyols are commercially available. The3-isocyanatopropyltrimethoxysilane, 3-isocyanatotriethoxysilane and(isocyanatomethyl)trimethoxysilane are also commercially available.

Suitable solvents for synthesis of the polyurea are those that are notreactive with isocyanate groups. These solvents include, but are notlimited to, xylenes, light aromatic naphtha, mineral spirits, butylacetate, 1-methoxy-2-propyl acetate, tert-butyl acetate, butylpropionate, pentyl propionate, ethyl 3-ethoxypropionate,parachlorobenzotrifluoride, tetrahydrofuran, 1,4-dioxane,dimethylacetamide, and N-methyl pyrrolidone.

The second component (part B) includes the epoxy- or acrylate-functionalcompound, which may be any compound that includes an amine-reactiveepoxy or acrylate group, or any mixture of such compounds. Suitableepoxy- or acrylate-functional compounds include, but are not limited to,an epoxy-functional dimethylpolysiloxane, an epoxy-functionalpolydimethyldiphenylsiloxane, an aliphatic epoxy, a cycloaliphaticepoxy, an acrylate-functional dimethylpolysiloxane, or1,6-hexanedioldiacrylate.

A catalyst may be used to accelerate the rate of hydrolysis of thealkoxysilane groups and to facilitate crosslinking of the resultingsilanol groups to form a cured coating. Suitable catalysts include, butare not limited to, organic tin compounds, such as dibutyl tindilaurate, dibutyl tin diacetate, and dibutyl tin bis(2-ethylhexoate),metal alkoxides, such as titanium tetraisopropoxide, aluminumtriethoxide, and zirconium tetrabutoxide, titanium chelates, alkalines,such as potassium hydroxide, organic acids, inorganic acids, tertiaryamines, or mixtures thereof.

Suitable pigments include, but are not limited to, titanium dioxide,carbon black, red iron oxide, yellow iron oxide, copper phthalocyanineblue, sodium aluminum sulphosilicate, chromium oxide, cobalt chromitegreen spinel, chromium green-black hematite, nickel antimony titaniumyellow rutile, and manganese-based pigments.

Suitable fillers include, but are not limited to, amorphous silica,functionalized silica, talc, mica, wollastonite, calcium carbonate,glass beads, graphite, polymeric waxes, acrylic beads, polyurethanebeads, and ceramic microspheres.

Suitable additives include, but are not limited to, rheology modifiers,thickening agents, adhesion promoters, reinforcing agents, wetting anddispersing agents, anti-floating agents, flame retardants, ultraviolet(UV) absorbers, hindered amine light stabilizers (HALS), and flow andleveling agents.

The two components may be provided as a kit having each of thecomponents in its own container. The two component system may also bedescribed as a coating composition comprising the amine-functionalcompound, the alkoxysilane-terminated polyurea, and the epoxy- oracrylate-functional compound.

The 2K coating can be applied to a variety of substrates. Suitablesubstrates include, but are not limited to, epoxy primed surfaces,polyurethane primed surfaces, pretreatments, epoxy-based composites,weathered or abraded silicone alkyd coatings, weathered or abradedpolysiloxane coatings, bare steel surfaces, bare aluminum surfaces, barealuminum alloy surfaces, concrete, glass, ceramics, and plastics.

When the two components are mixed and applied to a surface, they maycure to form a solid coating. As in other 2K systems, the amine groupsof the amine-functional compound in the first component react with theepoxy-functional compound in the second component. When theamine-functional compound includes alkoxysilane groups, these groups mayalso hydrolyze and condense as shown below. The alkoxysilane groups ofthe polyurea may also undergo hydrolysis and condensation with eachother and with those of the amine-functional compound.

When the second component includes the acrylate-functional compound, theamine groups of the amine-functional compound undergo a Michael additionwith the acrylate groups as shown below.

Any of the polyureas disclosed herein may be used in a 1K system wherethe polyurea is moisture cured as described above. The moisture curingmay occur in the absence of other compounds that crosslink with thepolyurea. Any of the polyureas may also be used in 2K systems, coatingcompositions, and kits where one component contains the polyurea andeither an amine-functional compound or an epoxy- or acrylate-functionalcompound, and the other component contains the other of theamine-functional compound and the epoxy- or acrylate-functionalcompound. In 2K systems, the polyurea may be up to 50, 90, or 95 wt % ofthe total of the mixed components.

The polyureas may generally be made, among other methods, by a two-stepprocess. First, the amino-functional alkoxysilane is reacted with thepolyisocyanate. This forms an adduct having an unreacted isocyanategroup as shown above in Eq. (1). The adduct is then reacted with one ormore polyfunctional amino- and/or hydroxyl compounds and optionallyadditional polyisocyanate. In some embodiments, the adduct is reactedwith a combination of two or more different such compounds. For example,the adduct may be reacted with both a diamine and a diol. In someembodiments, the compounds collectively contain both amine and hydroxylgroups, such as the previously stated diamine and diol combination, orthe compound may be a single aminohydroxyl compound. Any free isocyanategroups do not react with other isocyanate groups in this reaction.

The reaction may produce a composition having a blend of products havingdifferent arrangements of the reactants. Individual products may have nounreacted isocyanate groups. FIG. 9 shows a number of possible productsthat could be present in the composition when usingN-butyl-3-aminopropyltrimethoxysilane, hexamethylene diisocyanate (dimerand trimer), a diamine, and a polyester diol. Certain compounds in thecomposition may have the formula of Eqs. (2), (3), or (8). Eq. (8),where m is 2 or 3 and each n is 1 or 2, depicts a compound having (fromright to left) a central polyisocyanate residue bound to 2 or 3difunctional amino and/or hydroxyl compound residues, each of which isbound to another polyisocyanate residue, each of which is bound to 1 or2 amino-functional alkoxysilane residues. Eqs. (2) and (3) show simplercompounds having a single, central diamine or diol residue bound to twopolyisocyanate residues, each of which is bound to one or moreamino-functional alkoxysilane residues.

{[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—X—R⁵—X—CO—NH}_(m)—R³  (8)

The following examples are given to illustrate specific applications.These specific examples are not intended to limit the scope of thedisclosure in this application. For examples that show only a polyureasynthesis, the polyurea may be used in the 2K system.

EXAMPLE 1

Aspartic ester-containing backbone—86 g (0.445 equiv.) of ahexamethylene diisocyanate homopolymer with mostly isocyanurate trimerstructure was dissolved in 74 g of pentyl propionate in a 500 mL 3-neckround bottom flask equipped with an Argon inlet and thermometer. Thiswas followed by the addition of 5 g of vinyltrimethoxysilane as a dryingagent. Using an addition funnel, 70.14 g (0.298 equiv.) ofN-butyl-3-aminopropyltrimethoxysilane was added dropwise to the solutionwhile keeping the temperature at 40-50° C. Next, 34.4 g (0.147 equiv.)of tetraethyl 2,2′-((2-methylpentane-1,5-diyl)bis(azanediyl))disuccinate(also known as aspartic acid, N,N′-(2-methyl-1,5-pentanediyl)bis-1,1′,4,4′-tetraethyl ester) was added dropwise while continuing to keep thetemperature at 40-50° C. After the addition was complete, the solutionwas stirred for an additional 30 minutes until the infrared (IR)spectrum indicated that no more free isocyanate (NCO) (2270 cm⁻¹)remained in solution. The polymer solution was calculated to have asolids content of 72.5% by weight. The main polymer structure is shownin FIG. 1.

A flat/matte gray coating was obtained using the following two-componentformulation:

Weight % of formula Part A Dibutyltin dilaurate 0.25 Amino-functionalpolydimethylsiloxane 17.61 Flexible polymer solution (FIG. 1) 8.76 PartB Cycloaliphatic epoxy 14.04 Epoxy-functional 11.09polydimethyldiphenylsiloxane Titanium dioxide 6.41 Carbon black 0.085Polyurea matting agent 8.55 Pentyl propionate 18.25 Ceramic microspheres14.96

The two parts were mixed at a 2:1 (B to A) ratio by volume and appliedon aluminum and tinplate panels using a 3 mil (˜75 microns) wet filmgauge. The coating was then allowed to cure at ambient conditions for 14days. The coating demonstrated a tack-free time of <1 hour, a dry-hardtime of <2 hours, a 60° gloss of 0.6 gloss units, an 85° gloss of 4.7gloss units, a Konig pendulum hardness of 17 oscillations, a resistanceof 100+ double rubs to a methyl ethyl ketone (MEK) soaked rag, a ¼″Mandrel Bend flexibility without cracking, and a GE Impact Flexibilityof 40% elongation. The coating has also demonstrated outstanding colorretention when subjected to accelerated weathering in a Xenon-ArcWeatherometer (WOM) chamber.

Two-component gloss white topcoats have also been formulated. An exampleof a coating with a 1:1 (A to B) mix ratio by volume is as follows:

Weight % of formula Part A Dibutyltin dilaurate 0.30 Amino-functional26.1 polydimethyldiphenylsiloxane 3-aminopropyltriethoxysilane 1.32Flexible polymer solution 10.83 Butyl propionate 3.14 Part BCycloaliphatic epoxy 25.8 Titanium dioxide 22.86 Butyl propionate 9.65

EXAMPLE 2

Other backbones—The flexible backbone of the urea polymers can bealiphatic, cycloaliphatic, aromatic, polyester, polyurethane,polycarbonate, polyether, polysulfide, polysiloxane or a combinationthereof, and the N-substituted groups can be C1-C12 alkyl, cycloalkyl,aryl, ester-containing aliphatic, ester-containing fluorinatedaliphatic, amide-containing aliphatic, polysiloxane, or any combinationthereof. An example of a polymer with a polyester backbone and N-butylsubstituted urea linkages is shown in FIG. 2. An example of a polymerwith a polydimethylsiloxane backbone and ester-containing N-substitutedgroups is shown in FIG. 3.

EXAMPLE 3

Bending test—A ¼″ Cylindrical Mandrel Bend was performed on the samples.FIG. 4 is a photograph showing the results of the bend test on a prior2K coating (left) that does not contain the polyurea polymer compared tothe presently disclosed coating (right) that does contain the polyureapolymer. The prior coating shows cracking along the bend while thepresent coating does not.

EXAMPLE 4

Polyurea based on an aliphatic polyisocyanate, N-alkyl amino-functionalalkoxysilanes, and a cycloaliphatic secondary diamine with N-alkylgroups—81.6 g (0.446 equiv.) of a hexamethylene diisocyanate homopolymerwith isocyanurate trimer structure was dissolved in 115 g of Aromatic100 (commercially available from Exxon) in a 500 mL 3-neck round bottomflask equipped with an Argon inlet and thermometer. This was followed bythe addition of 5 g of vinyltrimethoxysilane as a drying agent. Using anaddition funnel, 71.38 g (0.303 equiv.) ofN-butyl-3-aminopropyltrimethoxysilane was added dropwise to the solutionwhile keeping the temperature at 40-50° C. Next, 18.78 g (0.147 equiv.)of N-isopropyl-3-((isopropylamino)methyl)-3,5,5-trimethylcyclohexanaminewas added dropwise while continuing to keep the temperature at 40-50° C.After the addition was complete, the solution was stirred for anadditional 15-30 minutes until the infrared (IR) spectra indicated thatno more free isocyanate (NCO) (2270 cm⁻¹) remained in solution. Thepolymer solution was calculated to have a solids content of 60.6% byweight. The structure is shown in FIG. 5.

EXAMPLE 5

Polyurea based on an aliphatic polyisocyanate, N-substitutedamino-functional alkoxysilanes with butyl ester-containing groups, andan aliphatic secondary diamine with N-alkyl groups—35.5 g (0.194 equiv.)of a hexamethylene diisocyanate homopolymer with isocyanurate trimerstructure was dissolved in 60 g of Aromatic 100 solvent (commerciallyavailable from Exxon) in a 500 mL 3-neck round bottom flask equippedwith an Argon inlet and thermometer. This was followed by the additionof 2 g of vinyltrimethoxysilane as a drying agent. Using an additionfunnel, 40 g (0.130 equiv.) of butyl3-((3-(trimethoxysilyl)propyl)amino)propanoate (synthesized by reacting3-aminopropyltrimethoxysilane with butyl acrylate via a Michael Additionreaction) was added dropwise to the solution while keeping thetemperature at 40-50° C. Next, 4.17 g (0.064 equiv.) ofN¹,N³-diethylpropane-1,3-diamine was added dropwise while continuing tokeep the temperature at 40-50° C. After the addition was complete, thesolution was stirred for an additional 15-30 minutes until the infrared(IR) spectra indicated that no more free isocyanate (NCO) (2270 cm⁻¹)remained in solution. The polymer solution was calculated to have asolids content of 57.6% by weight. The structure is shown in FIG. 6.

EXAMPLE 6

Polyurea based on an aliphatic polyisocyanate, N-substitutedamino-functional alkoxysilanes with butyl-containing groups, acycloaliphatic secondary diamine with N-alkyl groups, and a polyesterdiol—A moisture-curable polymer was synthesized by adding 70.14 g ofN-butyl-3-aminopropyltrimethoxysilane (SIB1932.2, Gelest) dropwise to asolution of 86 g of an aliphatic polyisocyanate mixture based onhexamethylene diisocyanate dimers and trimers (Desmodur N-3400,Covestro) and 5 g of vinyltrimethoxysilane (Sigma-Aldrich) in 100 g ofpentyl propionate (Sigma-Aldrich) in a 500 mL round bottom flask undernitrogen. The temperature was kept at 50-60° C. for the entire addition.This was followed by the addition of 0.14 g of dibutyltin dilaurate(Sigma-Aldrich). A solution of 35.65 g of a polyester diol (Desmophen670, Covestro) and 9.39 g of cycloaliphatic secondary diamine1,3,3-trimethyl-N-(1-methylethyl)-5-[(1-methylethyl)amino]cyclohexanemethanamine(Jefflink 754, Huntsman) in 90 g of pentyl propionate was then addeddropwise to the solution of polyisocyanate. After the addition wascomplete the reaction was stirred for 3 hours. This was followed by 5.24g of N-butyl-3-aminopropyltrimethoxysilane and stirring for anadditional 10 minutes. FTIR showed that all of the isocyanate groups hasbeen consumed.

Obviously, many modifications and variations are possible in light ofthe above teachings. It is therefore to be understood that the claimedsubject matter may be practiced otherwise than as specificallydescribed. Any reference to claim elements in the singular, e.g., usingthe articles “a”, “an”, “the”, or “said” is not construed as limitingthe element to the singular.

What is claimed is:
 1. A polyurea made by a method comprising: reactingan amino-functional alkoxysilane with a polyisocyanate to form one ormore adducts having an unreacted isocyanate group; and reacting theadducts with one or more polyfunctional amino- and/or hydroxyl compoundsand a polyisocyanate to form the polyurea; wherein at least one of thepolyfunctional amino- and/or hydroxyl compounds comprises an aminogroup; wherein at least one of the polyfunctional amino- and/or hydroxylcompounds comprises a hydroxyl group; wherein isocyanate groups do notreact with other isocyanate groups; wherein the polyurea comprises atleast two residues of the polyfunctional amino-and/or hydroxylcompounds; and wherein the polyurea contains no unreacted isocyanategroups.
 2. The polyurea of claim 1, wherein the polyurea comprises oneof more compounds having the formula:{[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—X—R⁵—X—CO—NH}_(m)—R³ whereineach a is independently selected from 1, 2, or 3; wherein m is 2 or 3;wherein each n is independently selected from 1 or 2; wherein each X isindependently selected from —NR⁴— and —O—; wherein each R¹ group is anindependently selected alkyl group; wherein each R² and R⁴ isindependently selected from hydrogen, aryl, alkyl, cycloalkyl,ester-containing aliphatic, ester-containing fluorinated aliphatic,amide-containing aliphatic, and polysiloxane; wherein each R³ is anindependently selected residue of an aliphatic, cycloaliphatic, oraromatic polyisocyanate having 2 or 3 isocyanate groups; and whereineach R⁵ independently comprises a group selected from aliphatic,cycloaliphatic, aromatic, polyester, polyether, polysulfide,polyurethane, polycarbonate, polysiloxane, and any combination thereof.3. The polyurea of claim 2, wherein the polyurea comprises two or moredifferent R⁵ groups.
 4. The polyurea of claim 3, wherein the polyureacomprises one of more compounds having the formula:


5. The polyurea of claim 3, wherein the polyurea comprises one of morecompounds having the formula:


6. A method comprising: providing a composition comprising a polyureamade by a method comprising: reacting an amino-functional alkoxysilanewith a polyisocyanate to form one or more adducts having an unreactedisocyanate group; and reacting the adducts with one or morepolyfunctional amino- and/or hydroxyl compounds and a polyisocyanate toform the polyurea; wherein the polyurea comprises at least two residuesof the polyfunctional amino-and/or hydroxyl compounds; whereinisocyanate groups do not react with other isocyanate groups; and whereinthe polyurea contains no unreacted isocyanate groups; andmoisture-curing the composition.
 7. A coating made by the method ofclaim
 6. 8. A composition comprising: an amine-functional compound or anepoxy- or acrylate-functional compound; and a polyurea made by a methodcomprising: reacting an amino-functional alkoxysilane with apolyisocyanate to form one or more adducts having an unreactedisocyanate group; and reacting the adducts with one or morepolyfunctional amino- and/or hydroxyl compounds and a polyisocyanate toform the polyurea; wherein the polyurea comprises at least two residuesof the polyfunctional amino-and/or hydroxyl compounds; whereinisocyanate groups do not react with other isocyanate groups; and whereinthe polyurea contains no unreacted isocyanate groups.
 9. The compositionof claim 8, wherein the composition further comprises one or more of acatalyst, a reactive diluent, a solvent, a filler, a pigment, or anadditive.
 10. The composition of claim 8, wherein the amine-functionalcompound is a monoamine, diamine, or triamine.
 11. The composition ofclaim 8, wherein the amine-functional compound is an amino-functionalpolydimethylsiloxane, an amino-functional polydimethyldiphenylsiloxane,3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane,3-aminopropylmethyldiethoxysilane, 1-aminomethyltrimethoxysilane, analiphatic monoamine, an aliphatic diamine, a cycloaliphatic diamine, oran amino-functional polyether.
 12. The composition of claim 8, whereinthe composition does not comprise both the amine-functional compound andthe epoxy- or acrylate-functional compound.
 13. The composition of claim8, wherein the composition comprises both the amine-functional compoundand the epoxy- or acrylate-functional compound.
 14. The composition ofclaim 8, wherein the polyurea comprises one of more compounds having theformula:{[(R¹O)_(a)R¹_(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—X—R⁵—X—CO—NH}_(m)—R³ whereineach a is independently selected from 1, 2, or 3; wherein m is 2 or 3;wherein each n is independently selected from 1 or 2; wherein each X isindependently selected from —NR⁴—and —O—; wherein each R¹ group is anindependently selected alkyl group; wherein each R² and R⁴ isindependently selected from hydrogen, aryl, alkyl, cycloalkyl,ester-containing aliphatic, ester-containing fluorinated aliphatic,amide-containing aliphatic, and polysiloxane; wherein each R³ is anindependently selected residue of an aliphatic, cycloaliphatic, oraromatic polyisocyanate having 2 or 3 isocyanate groups; and whereineach R⁵ independently comprises a group selected from aliphatic,cycloaliphatic, aromatic, polyester, polyether, polysulfide,polyurethane, polycarbonate, polysiloxane, and any combination thereof.15. The composition of claim 14, wherein the polyurea comprises two ormore different R⁵ groups.
 16. The composition of claim 8, wherein theamino-functional alkoxysilane is N-butyl-3 -aminopropyltrimethoxysilane,3- aminoprop yltriethoxy silane, 3-aminopropyltrimethoxysilane,3-aminopropylmethyldiethoxysilane,N-methyl-3-aminopropyltrimethoxysilane, orN-[3-(trimethoxysilyl)propyl]-β-alanine butyl ester.
 17. The compositionof claim 8, wherein the polyisocyanate is hexamethylene diisocyanate, ahomopolymer of hexamethylene diisocyanate, toluene diisocyanate,isophorone diisocyanate, homopolymer of isophorone diisocyanate,methylene diphenyl diisocyanate, or a mixture thereof.
 18. Thecomposition of claim 8, wherein the polyfunctional amino- and/orhydroxyl compound is aspartic acid;N,N′-(2-methyl-1,5-pentanediyl)bis-1,1′,4,4′-tetraethyl ester; anunsaturated polyester diol; a caprolactone-based polyester diol; ahydroxyl terminated polymethylphenylsiloxane; or a hydroxyl-propylterminated polydimethylsiloxane.
 19. A method comprising: providing asecond composition comprising the epoxy- or acrylate-functional compoundhaving no unreacted isocyanate groups; mixing the composition of claim 8with the second composition to form a mixture; wherein the compositionof claim 8 comprises the amino-functional compound; applying the mixtureto a surface; and allowing the mixture to cure to a coating.
 20. Themethod of claim 19, wherein the second composition further comprises oneor more of a catalyst, a reactive diluent, a filler, a solvent, apigment, or an additive.
 21. The method of claim 19, wherein the amountof the polyurea in the mixture is up to 95 wt % of the mixture.
 22. Themethod of claim 19, wherein the epoxy- or acrylate-functional compoundis an epoxy-functional dimethylpolysiloxane, an epoxy-functionalpolydimethyldiphenylsiloxane, an aliphatic epoxy, a cycloaliphaticepoxy, an acrylate-functional dimethylpolysiloxane, an epoxy-functionalurethane, an acrylate-functional urethane, or 1,6-hexanedioldiacrylate.23. The method of claim 19, wherein the mixture is cured by one more of:hydrolysis and condensation of alkoxysilane groups; and amine/epoxy oramine/acrylate reactions.
 24. A coating made by the method of claim 19.25. A method comprising: providing a second composition comprising theamino-functional compound having no unreacted isocyanate groups; mixingthe composition of claim 8 with the second composition to form amixture; wherein the composition of claim 8 comprises the epoxy- oracrylate-functional compound; applying the mixture to a surface; andallowing the mixture to cure to a coating.
 26. A kit comprising: a firstcontainer containing the composition of claim 8; wherein the compositionof claim 8 comprises the amino-functional compound; and a secondcontainer containing a composition comprising the epoxy- oracrylate-functional compound having no unreacted isocyanate groups. 27.A kit comprising: a first container containing the composition of claim8; wherein the composition of claim 8 comprises the epoxy- oracrylate-functional compound; and a second container containing acomposition comprising the amino-functional compound having no unreactedisocyanate groups.
 28. A method comprising: providing a compositioncomprising a polyurea made by a method comprising: reacting anamino-functional alkoxysilane with a polyisocyanate to form an adducthaving an unreacted isocyanate group; and reacting the adduct with apolyfunctional amino- and/or hydroxyl compound to form the polyurea;wherein the polyurea contains no unreacted isocyanate groups; andmoisture-curing the composition.
 29. The method of claim 28, wherein thepolyurea comprises one of more compounds having the formula:{[(R¹O)_(a)R¹ _(3-a)Si—(CH₂)₃—NR²—CO—NH]_(n)—R³—NH—CO—X—}₂—R⁵; wherein ais 1, 2, or 3; wherein n is a positive integer; wherein X is —NR⁴— or—O—. wherein each R¹ group is an independently selected alkyl group;wherein each R² and R⁴ is independently selected from hydrogen, aryl,alkyl, cycloalkyl, ester-containing aliphatic, ester-containingfluorinated aliphatic, amide-containing aliphatic, and polysiloxane;wherein R³ is a residue of an aliphatic, cycloaliphatic, or aromaticpolyisocyanate having n+1 isocyanate groups; and wherein R⁵ comprises agroup selected from aliphatic, cycloaliphatic, aromatic, polyester,polyether, polysulfide, polyurethane, polycarbonate, polysiloxane, andany combination thereof.
 30. The method of claim 28, wherein thecomposition further comprises one or more of a catalyst, a reactivediluent, a solvent, a pigment, an additive, and a filler.
 31. A coatingmade by the method of claim
 28. 32. The coating of claim 31, wherein Xis —O—.
 33. A coating composition comprising: an amine-functionalcompound; a polyurea made by a method comprising: reacting anamino-functional alkoxysilane with a polyisocyanate to form one or moreadducts having an unreacted isocyanate group; and reacting the adductswith one or more polyfunctional amino- and/or hydroxyl compounds and apolyisocyanate to form the polyurea; wherein the polyurea comprises atleast two residues of the polyfunctional amino-and/or hydroxylcompounds; wherein isocyanate groups do not react with other isocyanategroups; and wherein the polyurea contains no unreacted isocyanategroups; and an epoxy- or acrylate-functional compound; wherein thecoating composition is a two-component system.